Multiple rotary evaporator



Sept. 19, 1967 Filed March 16, 1965 FIGI Condensate Catcher l. E. BUSH MULTIPLE ROTARY EVAPORATOR Coolant To Vacuum Pump Condensing Chamber 22 Coolani Chamber 2 Sheets- Sheet l INVENTOR IAN E. BUSH BY M2879 ATTORNEY I. E. BUSH Sept. 19, 1967 MULTIPLE ROTARY EVAPORATOR 2 Sheets-Sheet 2 Filed March 16, 1965 FIG. 6

FIG. 5

INVENTOR IAN E BUSH BY M f ATTORNEY United States Patent 3,342,696 MULTIPLE ROTARY EVAPORATOR Ian E. Bush, 30 Grafton St., Shrewsbury, Mass. 01545 Filed Mar. 16, 1965, Ser. No. 440,208 14 Claims. (Cl. 202-172 This invention relates to rotary or so-called flash evaporators which are used for distilling relatively small amounts of solvents particularly for laboratory use. The usual evaporator of the prior art takes up about 2 /2 of bench or frame space and thus it will be seen that Where a half-a-dozen of these apparatuses are required, a very large part of the bench space of even a moderate sized laboratory is taken up. This invention provides for a multiple evaporator whereby as many for instance as siX flasks can be conveniently handled by the technician in a bench space of approximately one foot, and by the use of this novel multiple arrangement a single motor drive and a single condensing system are possible so that the prior art separate vacuum leads and pumps for each flask are no longer necessary.

It is an object of the invention to provide for a more effective condensing system, the invention providing a much shorter and wider vapor path from the distilling vessel to the condensing zone, and this is achieved not only through the overall construction, and the means of motor drive, etc., but also to an improved bearing arrangement and an improved condensing system.

Another object of the invention resides in a new and improved valve means providing that any distilling flask, and also the receiving vessel, can be removed and changed Without breaking the vacuum and hence without interrupting the continuous operation of the apparatus.

, Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings in which:

FIG. 1 is a view in front elevation with parts broken away and in section illustrating a form of the invention;

FIG. 2 isan enlarged sectional view illustrating the valve and bearing details for the flask;

FIG. 3 is a section of the valve construction for the receiver of the condensate;

FIG. 4 is a section on line 4-4 of FIG. 3;

FIGS. 5 and 6 are sections of modified forms of such valves, and

FIG. 7 is a plan view illustrating the gearing.

Referring now to FIG. 1, there is shown a relatively elongated vertically arranged tube 10 of any suitable material as for instance glass and this tube may be supported on a bracket or stand of any convenient nature. At its lower end it is provided with the receiving flask 12 which of course is detachable as will be explained hereinafter. The flask 12 receives the condensate.

The tube 10 is provided with an outlet 13 for a lead or conduit to a vacuum pump and it also has an interior tube 14 which forms the condensing chamber generally indicated at 16. The tube may be made of metal such as stainless steel and the tubes can be provided with encircling vanes such as are indicated at 18, to direct the condensate to the distal side of chamber 16. If made of metal there should be a transparent portion adjacent the top forming a window for the observation of the bubbling of the coolant to avoid the risk of spillage particularly where such coolant may be in the form of CO or the like. Alternatively a tube such as at 20, 20 may be run down through the entire coolant chamber 22 to provide for continuous flow of coolant materials and preferably the inner tube 14 should be removably secured to the outer.

tube 10 for the purposes of inspection, servicing, etc.

There are three vapor entrances shown leading to the condensing chamber 16 but of course any number is possible as may be found desirable. Each entrance is defined by a sleeve 26 preferably of glass like the outer tube 10, and conveniently they slope downwardly from the condenser to the left as clearly shown in FIG. 1. To these sleeves are attached the distilling flasks 28, 28, 28.

The condensate or receiving flask 12 is removably attached as for instance by a sliding sleeve or tube generally indicated at 30. This member is cylindrical and at its lower end has a standard cone joint 32 for the attachment of a standard flask, i.e., receiver 12.

The sliding sleeve or tube 39 closely fits and slides vertically in a block or bracket 34 attached in any way desired in an extension 36 at the lower end of the outer tube 10. This block has a standard socket tapered interior portion at 38 which closely fits the similarly tapered upper end of the slide valve as at 40 and this provides a tight seal during the operation, i.e., during the period when the flask 12 is receiving the condensate, see FIG. 4.

The block or bracket 34 carries a slide valve 42 on which is mounted a pair of guides 44 closely receiving and holding the slidable tubes 30. In order to change flasks without breaking the vacuum it is merely necessary to pull down the sleeve or tube 30 which is receiving to the FIG. 3 position, move the slide valve 42 so that it covers the opening 38 in the bracket 34 and continue until the other guide 44 is aligned with opening 38. The nonaligned fiask can now be changed. The aligned flask 12 is pushed upwardly as well as its tube 30, and no inter-.

ruption either to the vacuum or to the reception of the condensation takes place.

Now referring to the construction for the distilling flask, it is preferably heated by a steam jet indicated by the reference numeral 50. A trough diagrammatically shown at 52 collects the water. The distilling flask is standard and it has a neck 54 which has: a standard cone fit with a tapered end of a sliding valve 56, see FIG. 2. This valve is slidingly mounted in a block 58 and it has an annular ring 60 intermediate the ends thereof. Adjacent its inner end it is provided with openings 62, 62 and is closed by a cap 64. The block 58 is screw-threaded or otherwise secured to a relatively short rotary sleeve 66 and the block 58 has an inwardly extending skirt or sleeve 68.-Thus valve 56 can be moved to a closed position where it is withdrawn as far as the cap 64 will allow and the apertures 62 will be obscured or blocked off by the skirt 68.

This valve can be locked to the block 58 as for instance by a semi-collar 70 fitting over the ring 60 or a conventional type of bayonet joint or the like can be used for this purpose and thus the valve body is held in its inwardmost operative position.

Reference numeral 72 represents a gear which is fast to the sleeve 66 and this gear is rotated as for instance by bevel gears from a main drive shaft 74 and a motor as generally indicated in FIG. 1 at 76. This motor can be supported in any way desired.

I Sleeve 66 has attached to it another sleeve 78 also preferably of glass and this can be secured thereto as by the threaded sleeve 80. A thrust bearing 82 is utilized between the two, the race for the bearing at 84 being utilized as a member for rotatably securing sleeve 66 and 78, with respect to the sleeve 26, the latter being permanently a part of the condensing tube 10 as shown in FIG. 1 and having a terminal lip 79 for this purpose. The parts 26 and 78 have a ground and lap fit and are preferably lubricated with silicone grease.

FIGS. 5 and 6 show modifications of the valve construction for the flask 12. In FIG. 5 the reference numeral 86 represents an equivalent to the block 34. It has A rotatably mounted on it another block 88 by a stud 90 and has two guides 92, 92 for sliding tubes similar to those at 30, indicated at 94, 94. To change it is merely necessary to pull the tube 94 to the right in FIG. 5 downwardly to the position shown at the left-hand side of the figure and index the block 88 to a point where as shown at the left it is blocked off. Then the full receiving flask can be changed and the empty one moved up into the block 88. Proper lubricants, etc. are used between the blocks 86 and 88 to provide a seal.

FIG. 6 shows a similar device having a manually rotatable valve of the shape shown and indicated at 96 located in a tube 98 mounted in block 100 which again is the equivalent of that at 34. In this case there are two branched guides 102 and 104 and each of these has a flask 12 applied to it. The valve 96 is turned to direct the condensate to a selected flask without the loss of vacuum, and the filled flask can be removed and replaced as will be clear to those skilled in the art.

It will be clear that the advantages of this invention are very appreciable. Many samples can be evaporated under reduced pressure at the same time on a single compact apparatus which takes up only about a foot of bench space. But a single condensing unit of a safe and convenient nature provides for the use of convenient and economical amounts of coolant under safe conditions. Only one motor drive is needed for all of the flasks.

Furthermore a very short broad vapor path leads with maximum efliciency to the condensing surfaces and also a jet can be applied to the sleeve 66 so that condensation is prevented prior to the main condensing zone. The sloping vanes deflect the condensate to the distal side so that the film of condensate on the condensing surface immediately opposite the entry point of each flask unit is of minimum thickness, thus increasing the rate of condensation at that point and the overall efliciency. The metal condensing surface increases the rate at which latent heat of condensation is transferred to the coolant and maintains maximum possible temperature gradient between distilling and condensing zones. The vacuum-sealed bearing for the distilling flask is of large diameter and considerable length, thus obtaining a good seal when lubricated with minimum mechanical fricton against rotation. This bearing is easily dismantled for servicing and inspection and it is easy to make with common materials.

The valves which are here provided allow any distilling flask as well as the receiving vessel to be removed and changed without breaking the vacuum and hence without any interruption to the continuous operation.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

1. A multiple rotary evaporator structure comprising a relatively elongated tubular condensing chamber, a series of sleeves arranged along an exterior surface of said condensing chamber, each sleeve being open to the chamber, means for detachably and operatively securing a distilling flask with respect to each sleeve, means for rotating said last-named means and thereby said distilling flasks, a source of power, means operatively connecting the power source to each one of said flask-attaching means for rotating the same in unison, heating means for each flask to provide for evaporation of the contents and transfer of the distillate to the condensing chamber, each flask having a free and clear path to the latter.

2. The evaporating structure of claim 1 wherein the condensing chamber is substantially vertical and the sleeves are arranged in a substantially vertical line.

3. A multiple rotary evaporator structure comprising an outer elongated tubular member and an inner elongated tubular member, said members being substantially vertical and being spaced and forming between them an enclosed substantially vertical condensing chamber, pump means providing a negative pressure in the chamber, the

inner tubular member being arranged to receive a coolant, a series of fixed sleeves projecting laterally from the outer tubular member, said sleeves being open to the chamber, other sleeves rotatably mounted one each on said first-named sleeves, and means to rotate simultaneously all of said last-named sleeves, a distilling flask on each rotatable sleeve, a projection forming an opening at the lower end of the outer tube, a detachable condensate receiving flask mounted on said projection, heating means to provide for evaporation and pressure in each flask, each flask having a clear path to the condensing chamber, and a valve for each rotatable sleeve for disconnecting each flask from the condensing chamber.

4. The rotary evaporator of claim 3 wherein said valves are movable between open and closed positions thereof, the distilling flasks being moved with their respective valves.

5. The rotary evaporator of claim 3 wherein said valves are movable between open and closed positions thereof, the distilling flasks being moved with their respective valves, each said valve comprising a hollow sleeve-like member having apertures therein, and means on each said second-named sleeve closing said apertures in one selected position of a respective valve and being clear thereof in the other position, the latter being the open operative position thereof.

6. A multiple rotary evaporator structure comprising an outer elongated tubular member and an inner elongated tubular member, said members being spaced and forming between them an enclosed condensing chamber, pump means providing a negative pressure in the chamber, the inner tubular member being arranged to receive a coolant, a series of fixed sleeves projecting laterally from the outer tubular member, said sleeves being open to the chamber, other sleeves rotatably mounted one each on said first-named sleeves, and means to rotate simultaneously, said rotary sleeves, a valve mounted on each of said rotary sleeves, each valve having a tapered end portion adapted to receive the neck of a distilling flask, a distilling flask on each said tapering necked portion of its valve, a detachable condensate receiving flask mounted on the outer elongated tubular member and heating means to provide evaporation and pressure in each flask.

7. A rotary evaporator as set forth in claim 6 wherein each valve is provided with means for completely closing its rotary sleeve whereby each distilling flask can be removed therefrom without interrupting the vacuum in the condensing chamber.

8. A multiple rotary evaporator comprising an outer tube, a spaced inner tube, said tubes between them forming a condensing chamber, pump means providing a vacuum for the latter, means detachably securing a receiving flask at one end of the outer tube, said inner tube receiving coolant, a series of glass sleeves on said outer tube, said sleeves being open to the condensing chamber, a second glass sleeve rotatably mounted on each of said first-named glass sleeves, drive means to rotate the second-named sleeves, and means associated with each rotary sleeve for the detachable reception of a distilling flask for cooperative sealing relationship with respect to said sleeve.

9. The multiple rotary evaporator recited in claim 8 wherein the inner tube of said condensing chamber is provided With a metal condensing surface.

10. The multiple rotary evaporator recited in claim 8 including vanes located between the two tubes directing condensate to the far-side of the condensing chamber from the sleeves.

11. An evaporator of the class described comprising a pair of tubes comprising inner and outer walls providing a condensing chamber between them, means providing for the admission of vapor into said condensing chamber, an opening at one end of said outer tube, a movable valve body mounted in respect to said opening, a plurality of valves on the valve body, and a detachable condensate wherein one valve closes the chamber to the atmosphere 5 in the absence of the flask, and the other wherein the same valve is open to the chamber in the presence of the flask.

12. The evaporator of claim 11 wherein said movable valve body is slidable.

13. The evaporator of claim 11 wherein said movable valve body is rotatable.

14. The evaporator recited in claim 11 wherein said valve body includes a slidable mount slidable to a position aligning one valve with the opening and at the same time misaligning another valve in the mount with respect to said opening, whereby the misaligned flask may be removed from the valve body and replaced Without uncovering the opening to the atmosphere.

References Cited UNITED STATES PATENTS 2,089,796 8/1937 Hopf et a1. 23--259 X 3,111,136 11/1963 Persidsky 137-62541 FOREIGN PATENTS 96,824 5/ 1924 Austria. 545,262 2/1932 Germany.

5 Developments, April 1962, digested copy in Class NORMAN YUDKOFF, Primary Examiner. J. SOFER, Assistant Examiner. 

1. A MULTIPLE ROTARY EVAPORATOR STRUCTURE COMPRISING A RELATIVELY ELONGATED TUBULAR CONDENSING CHAMBER, A SERIES OF SLEEVES ARRANGED ALONG AN EXTERIOR SURFAE OF SAID CONDENSING CHAMBER, EACH SLEEVE BEING OPEN TO THE CHAMBER, MEANS FOR DETACHABLY AND OPERATIVELY SECURING A DISTILING FLASK WITH RESPECT TO EACH SLEEVE, MEANS FOR ROTATING SAID LAST-NAMED MEANS AND THEREBY SAID DISTILLING FLASKS, A SOURCE OF POWER, MEANS OPERATIVELY CONNECTING THE POWER SOURCE TO EACH ONE OF SAID FLASK-ATTACHING MEANS FOR ROTATING THE SAME IN UNISON, HEATING MEANS FOR EACH FLASK TO PROVIDE FOR EVAPORATION OF THECONTENTS AND TRANS- 